基于Jave的Web服务工作机制(6)_Windows教程

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 parseUri 方法从请求行那里得到URI。Listing 1.3 展示了parseUri 方法的用途。 parseUri 减缩请求中的第一个和第二个空格来获得URI。

  Listing 1.3. The Request class' parseUri method

  private String parseUri(String requestString) {
  int index1, index2;
  index1 = requestString.indexOf(' ');

  if (index1 != -1) {
    index2 = requestString.indexOf(' ', index1 + 1);
    if (index2 > index1)
     return requestString.substring(index1 + 1, index2);
  }

  return null;
}

  Response类

  Response表示一个HTTP响应。它的构造函数接受一个OutputStream对象,比如下面的:

  public Response(OutputStream output) {
  this.output = output;
  }
  Response 对象被HttpServer类的await方法构造,该方法被传递的参数是从socket那里得到的OutputStream对象。

  Response类有两个公共方法: setRequest和sendStaticResource. setRequest方法传递一个Request对象给Response对象。Listing 1.4中的代码显示了这个:

  Listing 1.4. The Response class' setRequest method

  public void setRequest(Request request) {
  this.request = request;
  }
  sendStaticResource 方法用来发送一个静态资源,比如HTML文件。Listing 1.5给出了它的实现过程:

  Listing 1.5. The Response class' sendStaticResource method

  public void sendStaticResource() throws IOException {
  byte[] bytes    = new byte[BUFFER_SIZE];
  FileInputStream fis = null;

  try {
    File file = new File(HttpServer.WEB_ROOT, request.getUri());
    if (file.exists()) {
      fis  = new FileInputStream(file);
      int ch = fis.read(bytes, 0, BUFFER_SIZE);

      while (ch != -1) {
        output.write(bytes, 0, ch);
        ch = fis.read(bytes, 0, BUFFER_SIZE);
      }
    }
    else {
      // file not found
      String errorMessage = "HTTP/1.1 404 File Not Found\r\n" +
        "Content-Type: text/html\r\n" +
        "Content-Length: 23\r\n" +
        "\r\n" +
        "<h1>File Not Found</h1>";
      output.write(errorMessage.getBytes());
    }
  }
  catch (Exception e) {
    // thrown if cannot instantiate a File object
    System.out.println(e.toString() );
  }
  finally {
    if (fis != null)
      fis.close();
  }
}

来源:网络搜集//所属分类:Windows教程/更新时间:2013-04-15
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